Mercury in Tuna Sushi Higher at Restaurants

May 22, 2010|34,122views

Tuna sushi from a supermarket may be safer to eat than sushi from a high-end restaurant.

A new study using fish DNA suggests that some species of tuna, particularly those used by restaurants, have higher mercury levels.

However, Live Science reports:

“Overall, however, all the tuna had pretty high mercury levels. The levels were, on average, greater than the concentrations considered safe to consume in one day by the U.S. Environmental Protection Agency and higher than the concentrations allowed in Japan.”

Dr. Mercola's Comments:

You may think that the tuna steaks and raw sushi served in higher-end restaurants would be safer than what you typically find in your local grocery store. But according to this report, toxicological testing reveals that tuna sold in restaurants actually contain HIGHER amounts of mercury than the store bought variety.

The reason for this is because restaurants tend to favor certain species of tuna, such as bluefin akami and bigeye tuna. Unfortunately, mercury tends to accumulate to a greater degree in muscle than in fat, rendering these highly prized, leaner species of tuna more susceptible to high contamination.

Another explanation is that restaurants tend to buy larger sized fish, which in turn contain larger concentrations of mercury due to their size. Remember the larger the fish the longer it has lived, and the more time it has had to bioaccumulate toxins like mercury from the ocean.

Toxin-Free Tuna is Hard to Find…

I rarely eat fish anymore, unless I’m able to verify that it is not contaminated. And based on tests conducted during the past several years, it’s clear that finding uncontaminated fish is getting more and more difficult. For example, a recent study from the U.S. Geological Survey detected mercury in every single fish sample from streams across the United States.

Here too, they found that ALL tuna tested contained fairly high amounts of mercury.

Live Science writes:

“The levels were, on average, greater than the concentrations considered safe to consume in one day by the U.S. Environmental Protection Agency and higher than the concentrations allowed in Japan.”

This is yet another blow against fish consumption in general, and tuna sushi rolls in particular.

Buyer Beware: All Fish Come with Health Risks, but Some are Worse than Others

There’s really no way for you to know how much mercury a piece of tuna (or any other fish) might contain, which is why I recommend avoiding fish as much as possible – especially tuna, whether raw or cooked.

However, knowing which species of tuna and other types of fish tend to accumulate higher amounts of toxins can at least help you avoid the highest risk, should you choose to eat it anyway.

Of the various tuna species tested in this study, the bluefin akami and bigeye tuna species fared the worst. These species had significantly higher levels of mercury than bluefin toro and yellowfin tuna.

In fact, the average mercury levels in bluefin akami exceeded the US FDA permissible limit for mercury (1 part per million), which is a level that no pregnant woman or child should ever consume, and a level considered unsafe for most people.

Yellowfin tuna are also a leaner species of tuna, but still don’t accumulate as much mercury as the akami.

“They might have lower mercury levels for a few reasons,” Live Science writes. “They are smaller than other tuna, don't eat as much, and tend to be killed at younger ages, so they don't accumulate mercury for as long as other species.”

Three years ago, "The Madison Declaration on Mercury Pollution" declared a general world-wide warning to the public to be careful about how much and which fish you eat, stating that increasing mercury concentrations are now being found in a number of fish-eating wildlife species in remote areas of the planet.

In fact, the rate of mercury contamination in tuna and other Pacific fish has steadily increased, rising 30 percent since 1990.

Other fish that tend to contain potentially hazardous levels of mercury include:

Smaller fish like sardines, however, are not as susceptible to contamination.

If for some reason you believe that farmed fish is the answer, think again. Farmed fish is typically even more polluted than wild-caught fish!

Farmed salmon, for example, which is being eaten in increasing amounts by millions of Americans, have been found to contain high levels of dangerous PCBs – yet another potent toxin. One study found concentrations of PCBs were 16 times higher than those of wild, ocean-fished salmon.

Again, I recommend you eat fish very sparingly, and avoid it altogether if you’re pregnant or planning a pregnancy.

Pregnant? Take Fish Off Your Menu, but Remember to Add Omega-3 from Other Sources!

It’s important to realize that mercury is a neurotoxin that is easily transferred to your child while in the womb.

If you have high levels of mercury in your system, from eating a lot of fish for instance, you could be putting your baby at risk. Studies have shown thatthe level of mercury in the umbilical cord blood of newborns is 1.7 times higher than the mercury level in their mother's blood.

Eating fish just two or more times a week has been found to raise mercury levels seven times beyond those in women who had not eaten any fish for a month, according to the CDC.

With this in mind, if you are pregnant or planning to become pregnant, please avoid eating fish unless you can verify, via lab testing, that it does not contain mercury.

Now, once you abstain from fish, it becomes even more critical to make sure you’re getting healthy omega-3 fat from some other animal source.

Omega-3’s are particularly important for the healthy development and growth of your baby. In fact, omega-3 fat, especially DHA (docosahexaenoic acid), is so essential to a child's development that if you -- and therefore your child -- are deficient in it, your child's nervous system and immune system may never fully develop, and it can cause a lifetime of unexplained emotional, learning, and immune system disorders.

Safe Alternatives Still Exist

Fortunately, there are still safe and effective ways to get all the health benefits of animal-based omega-3, without the risks of toxic contaminations.

Smaller fish are far less likely to be contaminated, so sardines and other tiny fish would likely be relatively toxin free. You can also stick to eating only what you know is clean, non-contaminated fish. One such option is Vital Choice Alaskan salmon, which I have had tested on numerous occasions and can vouch for as being mercury free.

Lastly, you can take a high-quality omega-3 supplement.
I prefer krill oil over fish oil, for several reasons. To learn more about the superior benefits of krill oil versus fish oil, please review this previous article. And as far as dealing with mercury toxicity, krill is probably one of the absolute best choices, as krill are tiny little crustaceans that have very little time to accumulate toxins.

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